Implications of geomorphology for the management of wetlands in drylands

    Research output: Chapter in Book/Report/Conference proceedingConference abstract

    Abstract

    The form and functioning of rivers and wetlands change over time in response to extrinsic controls such hydrology and human activities, and intrinsic factors such as erosion and sedimentation. The resulting geomorphological and ecological dynamics can be problematic for river and wetland management, especially for wetlands in drylands that typically have a negative annual water balance and provide essential ecosystem services in moisture-limited landscapes. Changes in the location, extent and integrity of channels and wetlands on the floodplain can lead to significant changes in ecosystem responses to flooding, and can influence ecological succession. Avulsion, the process of channel relocation on the floodplain, can shift the foci of flooding and associated aquatic habitats within years or decades in some systems, at times confounding efforts to maintain wetlands within established conservation boundaries. Historically, management responses to geomorphological changes tended to involve ‘harder’ engineering approaches; for example, installation of weirs, embankments and canals to impede, divert, spread or convey water and to control erosion in channels and wetlands. However, the consequences of introducing these artificial structures include disturbance of flow and inundation regimes, exacerbation of erosion and sedimentation, alteration of channel-floodplain connectivity, modification of geomorphic units and landforms, and changes to ecological processes and habitats. ‘Softer’ approaches make use of fluvial processes and vegetation to ‘work with nature’ in order to achieve desired management outcomes. For example, engineered log jams may increase roughness in channels and geotextile-lined buffer zones may reduce flow velocity, control erosion, and encourage establishment of vegetation. However, wetlands in drylands, by their nature, have irregular flood and drought regimes, seasonal aquatic habitat growth and decay, and are profoundly influenced by fire, creating complex, mosaic-like ecosystems that defy simple approaches to management. Furthermore, water resource developments and land-use change at the catchment scale are key environmental stressors on wetlands in drylands that cannot be managed directly. Examples from Australia show that management strategies for wetlands in drylands are starting to account for internal morphodynamics and feedbacks between geomorphology and the ecosystem responses related to channel and inundation change, but long-term sustainable use of wetlands in drylands will rely on catchment- and site-appropriate implementation of holistic and adaptive management practices.
    Original languageEnglish
    Title of host publication2016 The 10th INTECOL International Wetlands Conference
    Subtitle of host publicationhotspots of biodiversity and ecosystem services under global changes: September 19-24, 2016: conference abstracts
    Place of PublicationChangshu, China
    Pages324-325
    Number of pages2
    Publication statusPublished - 19 Sep 2016

    Keywords

    • avulsion
    • channel change
    • ecosystem response
    • floodplain
    • geomorphology
    • wetland management

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